Dailymail.co.uk | The boss of the company behind the devastated Japanese nuclear reactor today broke down in tears - as his country finally acknowledged the radiation spewing from the over-heating reactors and fuel rods was enough to kill some citizens

Japan's Nuclear and Industrial Safety Agency admitted that the disaster was a level 5, which is classified as a crisis causing 'several radiation deaths' by the UN International Atomic Energy.

Officials said the rating was raised after they realised the full extent of the radiation leaking from the plant. They also said that 3 per cent of the fuel in three of the reactors at the Fukushima plant had been severely damaged, suggesting those reactor cores have partially melted down.

After Tokyo Electric Power Company Managing Director Akio Komiri cried as he left a conference to brief journalists on the situation at Fukushima, a senior Japanese minister also admitted that the country was overwhelmed by the scale of the tsunami and nuclear crisis.

He said officials should have admitted earlier how serious the radiation leaks were.

CBSNEWS | Since the disaster struck in Japan, about 800 workers have been evacuated from the damaged nuclear complex in Fukushima. The radiation danger is that great.

However, CBS News correspondent Jim Axelrod reports that a handful have stayed on the job, risking their lives, to try to save the lives of countless people they don't even know. The exact number of workers is unclear and has been reported to be anywhere from 50 to 180.

Although communication with the workers inside the nuclear plant is nearly impossible, a CBS News consultant spoke to a Japanese official who made contact with one of the workers inside the control center.

The official said that his friend told him that he was not afraid to die, that that was his job.

Cham Dallas, who led teams responding to the Chernobyl disaster, said that kind of response is not out of the normal for some workers in the nuclear energy sector.

CNN | A second fire was discovered Wednesday in the Fukushima Daiichi nuclear plant, the latest in a series of setbacks at the stricken plant that has heightened fears that the incidents could lead to widespread radiation contamination.

The fire followed an explosion Tuesday at the plant's No. 2 reactor and a fire in a storage pond used for spent nuclear fuel at the No. 4 reactor. Radiation levels at the plant increased to about 167 times the average dose during that fire, according to the International Atomic Energy Agency.

The Diplomat | A steam explosion in one of the reactors at the nuclear power stations in Fukushima Prefecture hit by Friday’s devastating earthquake could see radiation spreading as far as Tokyo, a designer of the plant said Sunday.

Speaking at a press conference in Tokyo, Masashi Goto gave reporters a clear explanation of what he believes happened in the reactors at the Fukushima Daiichi (No.1) plant.

‘The problem was with the cooling system,’ said Goto, a former Toshiba employee specializing in containment vessel design. ‘Because this didn’t work, the temperature began to rise, and the water level began to drop. This exposed the upper parts of fuel rods and they started to melt.

‘The pressure in the containment vessel rose to about 1.5 times the level it was designed to withstand. The temperature in the pressure pool began to rise to over 100 degrees Celsius and pure water couldn’t be used to cool the system. People there tried to bring in (sea) water to cool the system.’

Goto said this was a difficult decision for officials as using sea water means there’s no guarantee the reactor can be used again, and, due to aftershocks, there is no guarantee that sea water can settle the reactor.

‘You need water, a pump and electricity to pump in water,’ he said. ‘Yet the entire site had no access to electricity, and two emergency diesel generators didn’t start up at the No. 1 reactor.

‘The build-up of pressure meant there was a real possibility of an explosion, which is why officials released a vent. By releasing radioactive materials into the air, you are defeating the purpose, but they had no choice.’

Goto believes the worst case scenario would be a steam explosion.

‘If water pumped into the system mixes with waste products, a steam explosion can occur,’ he said. ‘This is a physical explosion similar to magma from a volcano falling into water. This is very dangerous...This power plant has several reactors and if one goes off it could affect the others.’

Goto said this was a possibility and (depending on wind direction) could result in radiation reaching the Tokyo area, although he added: ‘No-one knows the exact situation inside the vessel.’

Bloomberg | Tokyo Electric Power Co. engineers tried to stabilize three nuclear reactors damaged by the biggest earthquake in Japan’s history after the plant was struck by a second explosion and as water levels dropped at one reactor, exposing fuel rods and increasing the threat of a meltdown.

The cooling system failed at the Dai-Ichi No. 2 reactor today, said Tokyo Electric, which runs the Fukushima nuclear plant 220 kilometers (135 miles) north of the nation’s capital. Fuel rods at the reactor may have melted after becoming fully exposed, Chief Cabinet Secretary Yukio Edano told reporters.

A hydrogen explosion occurred at the No. 3 reactor today, following a similar blast on March 12 at the No. 1 reactor that destroyed the walls of its building. The utility has been flooding the three reactors with water and boric acid to reduce the potential for a large release of radiation into the atmosphere following the March 11 earthquake-generated tsunami that smashed into the plant, disabling electricity supply and backup generators.